# def countdown(n):
#       while n > 0:
#             yield n
#             n -= 1

# generator = countdown(5)

# # 通过迭代生成器获取值
# print(next(generator))
# print(next(generator))
# print(next(generator))

# # 使用for循环迭代生成器
# for value in generator:
#       print(value)

import sys
def fibonacci(n):
      a,b,counter = 0, 1, 0
      while True:
            if (counter > n):
                  return
            yield a 
            a , b = b, a + b
            counter += 1
f = fibonacci(10)

while True:
      try:
            print(next(f),end=" ")
      except StopIteration:
            sys.exit()